Fish Nutrition

Reprinted with permission from the fall 2013 issue of Idaho
Author: Tara Roberts

The aquaculture industry is booming, and billions of people rely on farmed fish as their primary dietary protein source. As carnivores, most of today’s farmed fish feast on fish meal, which is made from other fish. But the world’s supply of fish meal can’t keep up with demand, said Ron Hardy, director of the University of Idaho’s Aquaculture Research Institute, or ARI, in Hagerman.

ARI researchers are investigating ways to replace fish meal with plant-based ingredients, opening doors for a more sustainable industry. A grant from the national Soy Aquaculture Alliance is supporting ARI research into feeding fish with the meal left over after cooking oil is extracted from soybeans. The research goes beyond traditional “feed ’em and weigh ’em” studies, Hardy said. ARI uses molecular techniques to analyze how high-soybean-meal feed affects fish, down to the genetic level.

The researchers not only investigate the effects of soy-based feed on everyday trout, but also have selectively bred a strain of rainbow trout that fare particularly well on a plant-based diet. The ultimate goal is to raise fish that grow quickly, efficiently and economically while remaining healthy, said ARI-based postdoctoral researcher Biswamitra Patro. ARI’s research into fish feed helps Idaho’s multimillion-dollar trout industry — No. 1 in the nation — and international farmers alike.

“Here we are in Idaho and we have this wonderful trout industry that is in a sense a microcosm of a global industry,” Hardy said. “The issues it faces are the same issues faced by the global aquaculture industry.”